Bally 6803

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1 Introduction

Inside the backbox of "Strange Science", which used the Turbo Cheap Squeak sound board and the "new" 14 digit plasma displays.

A look inside the backbox of "Eight Ball Champ", the first Bally 6803 game. Eight Ball Champ was designed to use either the Squawk & Talk sound board or the Cheap Squeak sound board. The game also used -17/-35 era 6/7 digit displays located on the lamp insert board.

The Bally 6803 game system, and the games themselves, were developed with extreme cost consciousness in mind. Bally used particle board cabinets with minimal artwork, backglasses illuminated by a single 115VAC light bulb, cheaper materials and short cut techniques during these years of game development. Still, many of these games continue to be enjoyed by hobbyists now and will be for years to come.

2 Games

Game Title	Game Number	Sound	Displays	Keypad Used	Notes
Eight Ball Champ	0B38	Squawk & Talk	4 7-Digit / 1 6-Digit	Yes
Beat the Clock	0C70	Squawk & Talk	4 7-Digit / 1 6-Digit	Assumed Yes
Lady Luck	0E34	Cheap Squeak	4 7-Digit / 1 6-Digit	Assumed Yes
Motordome	0E14	T. C. S.	2 "Special" 14-Alphnumeric	Yes
Black Belt	0E52	T. C. S.	2 "Special" 14-Alphnumeric	Assumed Yes
Special Force	0E47	Sounds Deluxe	2 "Special" 14-Alphnumeric	Yes
Strange Science	0E35	T. C. S.	2 "Special" 14-Alphnumeric	Yes
City Slicker	0E79	T. C. S.	2 "Special" 14-Alphnumeric	Yes
Hardbody	0E94	T. C. S.	2 "Special" 14-Alphnumeric	Yes
Party Animal	0H01	Sounds Deluxe	2 "Special" 14-Alphnumeric	Yes
Heavy Metal Meltdown	0H03	Sounds Deluxe	2 "Special" 14-Alphnumeric	Yes
Dungeons & Dragons	0H06	Sounds Deluxe	2 "Special" 14-Alphnumeric	Yes
Escape from the Lost World	0H05	Sounds Deluxe	2 "Special" 14-Alphnumeric	No
Blackwater 100	0H07	Sounds Deluxe	2 "Special" 14-Alphnumeric	No
Truck Stop	2001	D-11581-2001	2 "Special" 14-Alphnumeric	No	Uses a sound interface board to process signals for sound board
Atlantis	2006	D-11581-2006	2 "Special" 14-Alphnumeric	No	Uses a sound interface board to process signals for sound board

Game model numbers provided by the Internet Pinball Database - http://www.ipdb.org

3 Technical Info

3.1 MPU Board

Bally 6803 MPU Board

The Bally 6803 MPU incorporates all of the function of it's predecessors, the -17 and -35 MPUs, along with lamp and solenoid drive circuitry. The MPU is responsible for driving all game features other than sound, which is handled by one of several sound boards used in the 6803 game system run.

Architecturally, the board is similar to it's predecessors but employs the 6803 microprocessor along with two 6821 Peripheral Interface Adapters. It also contains what is essentially the entire lamp board circuitry along the left side of the board, including the familiar 4514 demultiplexers, 2N5064 SCRs and MCR-106 SCRs (silicon controlled rectifiers). Along the top of the MPU board, the solenoid driver circuitry of the older Bally Regulator/Solenoid Driver Board has been incorporated, including the typical 74LS154 4-to-16 decoder, CA3081 transistor arrays, and TIP-102 transistors. A "cube" relay, located in the upper right corner of the MPU, is used to complete the power circuit for the flippers and is energized only when a game is in play.

3.1.1 CPU Board ROM Info and Jumper Settings

Game	U2	U3	Jumpers
Eight Ball Champ	Not Used	0B38-00803-0005	2, 4, 6, 8, 10
Beat the Clock*	Not Used	0C70-00803-0005	2, 4, 6, 9, 10
Lady Luck	Not Used	0E34-00803-0005	2, 4, 6, 8, 10
Motor Dome	E14A-42AAE-BX40	E14A-42AAE-CX4D	2, 4, 6, 8, 10
Black Belt	0E52-00803-0001	0E52-00803-0002	2, 4, 6, 8, 10
Special Force	0E47-00803-0004	0E47-00803-0005	2, 4, 6, 9, 10
Strange Science	0E35-00803-0001	0E35-00803-0002	2, 4, 6, 9, 10
City Slicker	0E79-00803-0002	0E79-00803-0003	2, 4, 6, 9, 10
Hard Body	E94A-12601-0000	E94A-12602-0000	2, 4, 6, 9, 10
Party Animal	H01A-12601-0000	H01A-12602-0000	2, 4, 6, 9, 10
Heavy Metal Meltdown	H03A-12601-0000	H03A-12602-0000	2, 4, 6, 9, 10
Dungeons & Dragons	H06A-12601-0000	H06A-12602-0000	2, 4, 6, 9, 10
Escape from the Lost World	H05A-12601-0000	H05A-12602-0000	2, 4, 6, 8, 10
Blackwater 100	H07A-12601-0000	H07A-12602-0000	2, 4, 6, 9, 10
Truck Stop	H08A-12601-0000	H08A-12602-0000	2, 4, 6, 9, 10
Atlantis	2006-12601-0000	2006-12602-0000	2, 4, 6, 9, 10

*Beat the Clock manual may state W8 in, W9 out. However, there was a service bulletin after the game was released stating the opposite.

3.2 Power Supply Board

The power supply board from a 6803 based Bally game.

Solder joints on the single sided board are subject to fracture.

The Bally 6803 game system power supply board provides all of the voltages necessary to operate the game. Solder joints, as shown on the right are subject to fracture on the power supply board, especially since it's a single sided board. Reflowing these solder joints will solve many power problems.

3.3 Sound Boards

3.3.1 Squawk & Talk

Bally Squawk & Talk Sound Board

3.3.2 Cheap Squeak Sound Board

Bally Cheap Squeak Sound Board A080-91603-XXXX or Midway P/N M-051-00114-XXXX

The Cheap Squeak was designed as a lesser expensive sound board. It only utilizes a 6803 microprocessor, which allows it to function without 6821 PIAs and external RAM memory. This sound board is only capable of simple tones and sounds, but not speech. Although the Cheap Squeak is used in a handful of -35 based Bally games, Lady Luck is the only 6803 based game which uses it.

At power up, the Cheap Squeak's LED will flicker briefly, then flash, flash again, then turn on and stay on. Once the LED stays on, it seems to turn itself off for certain sounds, and then turn back on. Likewise, it appears to idle with the LED on, when no sounds are playing. The LED May turn on and off when sounds are playing or idle, but this is not always the case.

With Lady Luck, upon pressing the self test button (SW1), the sound board will play an explosion type noise. The board will then reboot itself.

Board Theory of Operations
The 6803 (U1) microprocessor multiplexes A0-A7 with D0-D7, calling those signals AD0-AD7. The processor fetches information from the sound ROMs (both code to execute and sound clips) by placing address information on AD0-AD7 and strobing the processor's AS (address strobe) signal to the 74LS373 (U2), thereby latching the lower 8 bits of the address bus in the LS373. A8-A15 are used along with jumpers JW1 through JW12, to implement a memory mapped I/O scheme to address the 2 sound ROMs which can be 2532s, 2732s, or 2764s. A14 and A15 control the 74LS10 (a triple 3-input nand gate) to assert device selects to the ROMs.

Note that the processor does not use the traditional R/W signal as it never "writes" to memory. Besides placing instruction address and data on the address and data busses, the processor reads sound selects via P20-P24 and writes sound data to the DAC via P10-P17. Think of these lines as PA1-PA7 of a 6821 or 6532.

The 6803 is initialized by the MPU at power up into 6803 mode N. Once initialized and running, the sound ROM code running in the 6803 accepts sound signal commands and merely reads pre-formatted sound "clips" from the sound ROMs and then writes the data to the ZN429 (U6) digital-to-analog converter (DAC) 8 bits at a time. The DAC converts the digital data to an analog level which is presented to the amplifiers for output to the speaker(s).

The board creates 5VDC on board by regulating 12VDC down to 5VDC. Unregulated 12VDC enters the board at J1-10. It is filtered by C8, C9, and C10. The inductor at L1 smooths the voltage somewhat. D6 (VR332, equivalent to a 1N5402), D7, and D8 drop the voltage by .5 - .7 volts (normal voltage drop across a diode). The 7805 at U9 further regulates the voltage down to 5VDC which can be measured at TP2 (TP3 is ground).

This 5VDC is used as a reference voltage by the amplifiers as well as to power the TTL logic ICs. The ZN429 DAC also uses this 5VDC as a voltage reference. To prevent the sound volume from fluctuating over the range of operating temperatures, the reference voltage is held constant by a "voltage divider biasing circuit" comprised of resistors at R22, R23, and R24, and a 2N5305 NPN transistor at Q7. This reference voltage is presented at pin 5 of the DAC.

Test Points

• TP1 should measure about 11VDC.
• TP2 is 5VDC.
• TP3 is ground.
• TP4 is the clock signal, provided externally by the 6803 for the purpose of synchronizing address and data read cycles.
• TP5 is the reset signal, which is also present on pin 6 of the 6803.
  

Bally Cheap Squeak Sound Board with Jumpers Highlighted

Jumpers JW2, JW4, JW7, JW10, and JW11 should be installed when U3 EPROM is installed for Lady Luck.

3.3.3 Turbo Cheap Squeak (T.C.S.)

The Bally Turbo Cheap Squeak (T.C.S.) Sound Board. Note that the headers, which are normally individual pins soldered directly to the board, have been replaced on this board. The test switch is also broken on this board.

The Turbo Cheap Squeak sound board was used on games like Strange Science and Motordome. The sounds it can produce are pretty basic.

The board features a 68B09EP processor, a 6821 PIA, 16K of static ram, and 256K of ROM. It interfaces to the MPU similarly to the Bally Squawk and Talk board. Volume is controlled by the pot at VR1.

Note that the board is marked "T.C.S. FOR PINBALL". Some Bally / Midway video games also use a Turbo Cheap Squeak sound board. The T.C.S. sound boards used for video games and pinball are not 1-to-1 compatible between one another.

The following games use the Cheap Squeak:

• Motordome
• Black Belt / Karate Kick
• Strange Science
• City Slicker
• Hardbody

Normal boot up diagnostics via the LED for the T.C.S is as follows:

• 1st Flash - Determines if the external ROM (U7) is good.
• 2nd Flash - Checks if the external RAM (U6) is good.
• 3rd Flash - Checks the 6821 PIA (U8).

3.3.4 Sounds Deluxe

Bally Sounds Deluxe Sound Board

3.4 Trough Optos

4 Opto Trough Transmitter Board

4 Opto Trough Receiver Board

Starting with Dungeons & Dragons, some 6803 series games used infared (IR) optic sensors for the trough switches. The more common transmitter and receiver boards used a total of 4 optic sensors. Escape from the Lost World only used a dual optic sensor transmitter and receiver. Blackwater 100 and Truck Stop used a 4 sensor board. Atlantis did not use an optic sensor board, but instead had a trough assembly with switches very much like Williams System 11 games.

The transmitter board consists of Motorola MLED930 IR emitters and current limiting resistors (68 ohm 1/2 watt). The receiver board consists Motorola MRD370 IR light detectors, 2N3904 transistors, and 390 Kohm 1/4 watt resistors. The transmitter board is powered by +5VDC.

3.5 Accessing Bookkeeping, Settings, and Diagnostics

6803 coin door test button

The single black button shown on the right side of the picture (just above the volume pot) causes the game to enter audits/diagnostics mode. All subsequent control of the game audits/diagnostics is done using the keypad (see below) in most cases. Some of the later 6803 games, such as Escape from the Lost World and Blackwater 100 abandoned the use of the keypad. Flipper buttons, auxiliary buttons (located below the flipper buttons) in combination with the start button are used to advance through bookkeeping, settings, and diagnostics.

On some earlier games, if the game detects a "stuck switch", it will make a hugely annoying sound until the stuck switch condition is corrected. Advice: turn the volume down. Later games would advance to attract mode regardless of stuck / closed switches.

3.5.1 6803 Keypad

The "beloved" 6803 keypad

As easy as "A, B, C"... Bally attemped to improve the operator's interface to the game system with this poorly constructed keypad. The keypad can be used to set free play, what kind of sounds are desired, balls per game, etc. See your game manual for game specific information.

The settings can be rather counter intuitive. For instance, setting (or register as it's called in the manual) 42 allows the operator to set the game to free play by entering "65".

Setting 27 allows the operator to configure the game sound style. Usually, you'll want this set to "3" which causes a "noise" effect when scoring occurs and enables background sound.

3.5.2 Built In Tests

Using the keypad to enter the following values begins the associated test. What could be more logical? ;-)

90 - Lamp Test
91 - Display Test
92 - Solenoid Test
93 - Sound Test
94 - Stuck Switch Test

4 Problems and Fixes

4.1 Power Problems

The power supply board from a 6803 based Bally game.

Solder joints on the single sided board are subject to fracture.

The Bally 6803 game system power supply board provides all of the voltages necessary to operate the game.

The 190VDC display voltage is derived from 170VAC input via the same circuitry as was used by the prior generation regulator/solenoid driver board. All of the same practices apply to this board including replacing the 25Kohm trim pot. The power supply shown at left has had the failed 160uf/350V high voltage filter cap replaced.
The 5VDC logic voltage is derived from 9.4VAC input, again using similar circuitry to the prior generation regulator/solenoid driver board. It's good practice to replace the 11,000uf/25V cap with a similar value. 12,000uf caps are a good choice. Here, a 15,000uf cap was used works fine.

The board also rectifies 49VAC to about 43VDC (probably a bit more) for use in solenoid circuits. General Illumination power (6.3VAC) also passes through the board, fused by two 15AFB fuses at FU6 and FU7.

The board shown at left still has the original 3/4 inch fuse in the high voltage section. When necessary, it's easy and advised to modify the board to accept the more common 1.25 inch fuses as shown here.

Solder joints, as shown on the right are subject to fracture on the power supply board, especially since it's a single sided board. Reflowing these solder joints will solve many power problems and is highly recommended.

4.1.1 Fuses and Test Points

The following table lists the circuit protection fuses for each circuit on the power supply.

FU1 - Solenoid Power - 5A SB (2 flippers), 6ASB (3 flippers), 7ASB (4 flippers)
FU2 - Display Power - 3/4A FB (a 3/4 inch fuse from the factory...suggest revising the power board to accept 1.25" fuses)
FU3 - 5V Logic Power - 6A SB
FU4, FU5 - 20VAC Controlled Lamp Power - 8A SB
FU6, FU7 - 6.3VAC General Illumination - 15A FB

The following test points are available on the power supply.

TP1 - 5VDC
TP2 - 190VDC, adjustable via the trim pot
TP3 - 230VDC, unregulated
TP4 - 43VDC
TP5 - 14VDC, unregulated
TP6 - 11VAC
TP7 - 11VAC
TP8 - 6.3VAC
TP9 - 6.3VAC
TP10 - Ground

4.2 MPU Issues

4.2.1 Relocating the Factory NiCad Battery off the MPU

The factory NiCad battery has been removed, a blocking diode has been added, and long leads provided so that the remote holder can lie comfortably in the bottom of the head.

Like other Bally and Stern MPUs that employ a battery on the MPU to provide power to the volatile RAM, it's a good idea to remotely locate the battery. The 6803 MPU provides an excellent place to locate a blocking diode so that the MPU charging circuit is blocked from attempting to charge the alkaline batteries. In the picture at left, two holes were drilled in the fat trace leading from the positive battery connection to the northwest. That trace was severed under the diode where the black line is shown, and the diode soldered across the severed trace with the banded end pointing away from the positive connection on the board. Be sure to provide enough wire to allow the remote holder to reach the bottom of the head making it impossible for leaky batteries to drip on the circuit boards.

4.2.2 Leon's 6803 CPU Repair

Leon's 6803 repair procedure has been added to the PinWiki, and can be found here: http://www.pinwiki.com/wiki/index.php?title=Leon_Borre_Bally_6803_repair

4.2.3 Replacing header pins

Original headers shown on left...new header on the right. Note the damage to the plating on the old pins.

Bally 6803 header pins are different from every other game system header pins. Bally used pins without a "carrier". Over time, the plating on these pins fails, creating conductivity issues. These header pins can be replaced fairly easily. Simply heat each pin individually and remove them. It's best to heat the pin itself vice the pin/board junction as quite a bit of heat is required to remove the pins, which are "jammed" into the board. Installing a new strip of .100 pins may require a bit of tapping with a hammer as the new pins are larger in diameter.

Replaced .156 headers on a Bally 6803 MPU.

The same procedure may be used for .156 header pins on the MPU, as shown at left.

4.3 Solenoid Problems

4.3.1 Slingshots Inoperative

Be advised that some 6803 games (perhaps all) have a setting, in "Basic Settings", to turn slingshots on or off during game play. If the slingshot switches register by scoring in game play or during switch test, and the slingshot solenoids fire in test but not in gameplay, examine this setting. 0 = Off during game play, 1 = On during game play.

4.4 Lamp Problems

Like the prior game system, Bally 6803 games did not use a lamp matrix. All controlled lamps are turned on via SCRs (silicon controlled rectifiers, either 2N5060s or MCR-106s) on the MPU board. The SCRs on the MPU must be refreshed (turned on) at 60Hz since SCRs turn off when the AC sine wave passes through zero (called the zero cross).

The usual techniques for dealing with lamp problems should be employed.

Lamp always on - It's probable that the associated SCR is shorted on.

Lamp never on...

Verify that the lamp is good by testing it in a working socket (like the backbox).
Verify that the lamp socket is good by jumping from a known good lamp socket to the suspect socket. If the lamp then lights, the socket and bulb are good.
Verify that the wire has not been severed by "buzzing" between the lamp socket and the associated lamp drive connector on the MPU.
Verify that the connector is working correctly by "buzzing" from the associated lamp drive SCR on the MPU to the lamp socket.
Test the SCR using the diode test.
Verify that the SCR is being turned on by the 4514.

An example of the worst lamp sockets ever used in a pinball machine.

In an effort to cut costs, the lamp socket style shown at left was used across quite a bit of the production run. While the "Spacer Invaders" era lamp sockets were bad, this style was even worse. Once a tab breaks off, it's not cost effective to repair them. Simply replace them with a new socket of the more conventional 3 tab style.
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4.6 Display Problems

4.6.1 Flickering Displays

Displays that form the characters properly, yet flicker at something like a 50% duty cycle (on half the time, off half the time) are sometimes caused by low high voltage DC.

Nominal display voltage is 190VDC but this voltage can be "trimmed" down using the trim pot. Doing so has the advantage of extending the life of the plasma displays. Measure DC voltage at TP2 as you trim the voltage, to at least ensure that the voltage isn't being turned up. At some point (well below that level), the displays will begin to flicker.

Sometimes the root cause of the reduced voltage is a failed or open HV filter cap. The OEM HV filter cap which was originally a 160uf/350V cap, can be replaced by a commonly available 150uf/350V cap.

An odd but possible reason for flickering displays.

One very unusual reason for flickering displays is caused when the outhole switch "fish paper" becomes dislodged and allows the switch blade(s) to touch game ground. The behavior caused is different from the flicker caused by low high voltage discussed above. This flicker generally manifests on the left display and the segments lit do not form characters but seemingly random "noise". This anomaly occurs when the ball is in the outhole, and the playfield is positioned in its normal state (not propped up).

4.7 Sound Problems

4.7.1 Sounds Deluxe Board

Bally Sounds Deluxe Sound Board

This sound board has a common problem with DAC failure. AD7533 chip is easy and inexpensive to replace. You can prevent failure by removing C12 (47 uf) capacitor. It seems to have no adverse affect but prevents a voltage condition on power down that can destroy the DAC.

The LED with flash a check sequence on power up. 6 Flashes ROMS and RAM are OK.

4.9 Coins Register But Don't Credit Up

This is commonly seen on VPinMAME emulation, but applies to real life as well.

Coins drop OK, switch is good, game makes noise, but it remains on "Credits 0" and doesn't credit up.

Symptom is corrupted/blank NVRAM.

To fix, open coin door (make sure coin door switch is working, otherwise the keypad won't work), then do these steps:

Hit "Test", to enter operator mode.

Hit "A" until "Feature Options" is displayed.

Hit Enter.

It will say "Reset Factory Is".

Hit 6, then 5, then Enter.

Hit "Game" to return to attract mode. You'll know it worked because it will take longer than usual to reach attract mode, and the display will flicker slightly as the computer clears the memory (this is normal).

Intuitive and easy to remember, right? And Bally had the nerve to advertise "manual-free testing"....

5 Game Specific Problems and Fixes

Example would be servo controller on Independence Day pinball

6 Repair Logs

Did you do a repair? Log it here as a possible solution for others.